Gas Fitter Practice Test

Where is the recommended location for a cooling coil on a suspended or horizontal furnace?

1. On the return air side

2. On the supply air side

3. On either side of the air circulating blower

4. Cooling coils are not recommended in these applications

The correct answer is: On the supply air side

The recommended location for a cooling coil in relation to a suspended or horizontal furnace is on the supply air side. This positioning is crucial because placing the cooling coil on the supply side ensures that the air has already been heated by the furnace before passing over the cooling coil. As a result, when the air circulates through the coil, it is efficiently cooled before being distributed into the living space. This setup helps maintain a consistent and comfortable indoor temperature, as the heated air is first conditioned by the furnace and then cooled, optimizing the thermal comfort of the environment. Furthermore, having the cooling coil on the supply side prevents potential condensation issues on the furnace itself, which could occur if the coil were located on the return air side. The choice to place cooling coils on the return air side could lead to inefficient cooling and possible moisture problems, as the air that returns can be too warm or humid, overwhelming the cooling capacity of the coil. Therefore, situating the cooling coil on the supply air side aligns with best practices in HVAC design and operation.